The present invention is concerned with a linear prediction based audio codec using frequency domain noise shaping such as the TCX mode known from USAC.
As a relatively new audio codec, USAC has recently been finalized. USAC is a codec which supports switching between several coding modes such as an AAC like coding mode, a time-domain coding mode using linear prediction coding, namely ACELP, and transform coded excitation coding forming an intermediate coding mode according to which spectral domain shaping is controlled using the linear prediction coefficients transmitted via the data stream. In WO 2011147950, a proposal has been made to render the USAC coding scheme more suitable for low delay applications by excluding the AAC like coding mode from availability and restricting the coding modes to ACELP and TCX only. Further, it has been proposed to reduce the frame length.
However, it would be favorable to have a possibility at hand to reduce the complexity of a linear prediction based coding scheme using spectral domain shaping while achieving similar coding efficiency in terms of, for example, rate/distortion ratio sense.
Thus, it is an object of the present invention to provide such a linear prediction based coding scheme using spectral domain shaping allowing for a complexity reduction at a comparable or even increased coding efficiency.